Peptide directed transmembrane transport and nuclear localization of Ru(ii) polypyridyl complexes in mammalian cells

2013 ◽  
Vol 49 (26) ◽  
pp. 2658 ◽  
Author(s):  
Lorraine Blackmore ◽  
Roisin Moriarty ◽  
Ciaran Dolan ◽  
Kellie Adamson ◽  
Robert J. Forster ◽  
...  
Keyword(s):  
Nuclear Localization ◽  
Mammalian Cells ◽  
Transmembrane Transport ◽  
Polypyridyl Complexes

Tyrosine phosphorylation controls nuclear localization and transcriptional activity of Ssdp1 in mammalian cells

2008 ◽  
Vol 103 (6) ◽  
pp. 1856-1865 ◽  
Author(s):  
Ipsita Dey-Guha ◽  
Nasir Malik ◽  
Renaud Lesourne ◽  
Paul E. Love ◽  
Heiner Westphal
Keyword(s):  
Tyrosine Phosphorylation ◽  
Nuclear Localization ◽  
Mammalian Cells ◽  
Transcriptional Activity

scholarly journals Staufen1 is imported into the nucleolus via a bipartite nuclear localization signal and several modulatory determinants

2005 ◽  
Vol 393 (1) ◽  
pp. 245-254 ◽  
Author(s):  
Catherine Martel ◽  
Paolo Macchi ◽  
Luc Furic ◽  
Michael A. Kiebler ◽  
Luc Desgroseillers
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Nuclear Export ◽  
Mammalian Cells ◽  
Rna Binding ◽  
Binding Activity ◽  
Nuclear Trafficking ◽  
Binding Domains ◽  
Bipartite Nuclear Localization Signal ◽  
Localization Signal

Mammalian Stau1 (Staufen1), a modular protein composed of several dsRBDs (double-stranded RNA-binding domains), is probably involved in mRNA localization. Although Stau1 is mostly described in association with the rough endoplasmic reticulum and ribosomes in the cytoplasm, recent studies suggest that it may transit through the nucleus/nucleolus. Using a sensitive yeast import assay, we show that Stau1 is actively imported into the nucleus through a newly identified bipartite nuclear localization signal. As in yeast, the bipartite nuclear localization signal is necessary for Stau1 nuclear import in mammalian cells. It is also required for Stau1 nucleolar trafficking. However, Stau1 nuclear transit seems to be regulated by mechanisms that involve cytoplasmic retention and/or facilitated nuclear export. Cytoplasmic retention is mainly achieved through the action of dsRBD3, with dsRBD2 playing a supporting role in this function. Similarly, dsRBD3, but not its RNA-binding activity, is critical for Stau1 nucleolar trafficking. The function of dsRBD3 is strengthened or stabilized by the presence of dsRBD4 but prevented by the interdomain between dsRBD2 and dsRBD3. Altogether, these results suggest that Stau1 nuclear trafficking is a highly regulated process involving several determinants. The presence of Stau1 in the nucleus/nucleolus suggests that it may be involved in ribonucleoprotein formation in the nucleus and/or in other nuclear functions not necessarily related to mRNA transport.

scholarly journals E2F activity is regulated by cell cycle-dependent changes in subcellular localization.

1997 ◽  
Vol 17 (12) ◽  
pp. 7268-7282 ◽  
Author(s):  
R Verona ◽  
K Moberg ◽  
S Estes ◽  
M Starz ◽  
J P Vernon ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Subcellular Localization ◽  
Nuclear Localization ◽  
Mammalian Cells ◽  
Critical Role ◽  
Biological Properties ◽  
Dependent Manner ◽  
Restriction Point ◽  
Cycle Dependent ◽  
Almost All

E2F directs the cell cycle-dependent expression of genes that induce or regulate the cell division process. In mammalian cells, this transcriptional activity arises from the combined properties of multiple E2F-DP heterodimers. In this study, we show that the transcriptional potential of individual E2F species is dependent upon their nuclear localization. This is a constitutive property of E2F-1, -2, and -3, whereas the nuclear localization of E2F-4 is dependent upon its association with other nuclear factors. We previously showed that E2F-4 accounts for the majority of endogenous E2F species. We now show that the subcellular localization of E2F-4 is regulated in a cell cycle-dependent manner that results in the differential compartmentalization of the various E2F complexes. Consequently, in cycling cells, the majority of the p107-E2F, p130-E2F, and free E2F complexes remain in the cytoplasm. In contrast, almost all of the nuclear E2F activity is generated by pRB-E2F. This complex is present at high levels during G1 but disappears once the cells have passed the restriction point. Surprisingly, dissociation of this complex causes little increase in the levels of nuclear free E2F activity. This observation suggests that the repressive properties of the pRB-E2F complex play a critical role in establishing the temporal regulation of E2F-responsive genes. How the differential subcellular localization of pRB, p107, and p130 contributes to their different biological properties is also discussed.

scholarly journals Evolutionary Selection of the Nuclear Localization Signal in the Viral Nucleoprotein Leads to Host Adaptation of the Genus Orthobornavirus

Viruses ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1291
Author(s):  
Ryo Komorizono ◽  
Yukiko Sassa ◽  
Masayuki Horie ◽  
Akiko Makino ◽  
Keizo Tomonaga
Keyword(s):  
Host Range ◽  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Mammalian Cells ◽  
Matrix Protein ◽  
Host Adaptation ◽  
Host Cells ◽  
Viral Glycoprotein ◽  
Mammalian Cell Lines ◽  
Localization Signal

Adaptation of the viral life cycle to host cells is necessary for efficient viral infection and replication. This evolutionary process has contributed to the mechanism for determining the host range of viruses. Orthobornaviruses, members of the family Bornaviridae, are non-segmented, negative-strand RNA viruses, and several genotypes have been isolated from different vertebrate species. Previous studies revealed that some genotypes isolated from avian species can replicate in mammalian cell lines, suggesting the zoonotic potential of avian orthobornaviruses. However, the mechanism by which the host specificity of orthobornaviruses is determined has not yet been identified. In this study, we found that the infectivity of orthobornaviruses is not determined at the viral entry step, mediated by the viral glycoprotein and matrix protein. Furthermore, we demonstrated that the nuclear localization signal (NLS) sequence in the viral nucleoprotein (N) has evolved under natural selection and determines the host-specific viral polymerase activity. A chimeric mammalian orthobornavirus, which has the NLS sequence of avian orthobornavirus N, exhibited a reduced propagation efficiency in mammalian cells. Our findings indicated that nuclear transport of the viral N is a determinant of the host range of orthobornaviruses, providing insights into the evolution and host adaptation of orthobornaviruses.

Nuclear localization and DNA interaction of protein disulfide isomerase ERp57 in mammalian cells

2002 ◽  
Vol 85 (2) ◽  
pp. 325-333 ◽  
Author(s):  
Sabina Coppari ◽  
Fabio Altieri ◽  
Anna Ferraro ◽  
Silvia Chichiarelli ◽  
Margherita Eufemi ◽  
...  
Keyword(s):  
Nuclear Localization ◽  
Mammalian Cells ◽  
Protein Disulfide Isomerase ◽  
Dna Interaction ◽  
Disulfide Isomerase ◽  
Protein Disulfide

scholarly journals K6-linked SUMOylation of BAF regulates nuclear integrity and DNA replication in mammalian cells

2020 ◽  
Vol 117 (19) ◽  
pp. 10378-10387 ◽  
Author(s):  
Qiaoyu Lin ◽  
Bin Yu ◽  
Xiangyang Wang ◽  
Shicong Zhu ◽  
Gan Zhao ◽  
...  
Keyword(s):  
Dna Replication ◽  
Nuclear Localization ◽  
Proliferating Cell Nuclear Antigen ◽  
Mammalian Cells ◽  
Regulatory Mechanism ◽  
Nuclear Antigen ◽  
Multiple Functions ◽  
And Function ◽  
Proliferating Cell ◽  
Replication Failure

Barrier-to-autointegration factor (BAF) is a highly conserved protein in metazoans that has multiple functions during the cell cycle. We found that BAF is SUMOylated at K6, and that this modification is essential for its nuclear localization and function, including nuclear integrity maintenance and DNA replication. K6-linked SUMOylation of BAF promotes binding and interaction with lamin A/C to regulate nuclear integrity. K6-linked SUMOylation of BAF also supports BAF binding to DNA and proliferating cell nuclear antigen and regulates DNA replication. SENP1 and SENP2 catalyze the de-SUMOylation of BAF at K6. Disrupting the SUMOylation and de-SUMOylation cycle of BAF at K6 not only disturbs nuclear integrity, but also induces DNA replication failure. Taken together, our findings demonstrate that SUMOylation at K6 is an important regulatory mechanism that governs the nuclear functions of BAF in mammalian cells.

scholarly journals The Fanconi Anemia Proteins FAA and FAC Function in Different Cellular Compartments to Protect Against Cross-Linking Agent Cytotoxicity

Blood ◽  
1998 ◽  
Vol 92 (7) ◽  
pp. 2229-2236 ◽  
Author(s):  
Frank A.E. Kruyt ◽  
Hagop Youssoufian
Keyword(s):  
Nuclear Localization ◽  
Fanconi Anemia ◽  
Nuclear Export ◽  
Mammalian Cells ◽  
Bone Marrow Failure ◽  
Cross Linking ◽  
Disease Genes ◽  
Macromolecular Complex ◽  
Subcellular Compartment ◽  
Nuclear Localization Signals

Abstract Fanconi anemia (FA) is an autosomal recessive disease characterized by chromosomal instability, bone marrow failure, and a high risk of developing malignancies. Although the disorder is genetically heterogeneous, all FA cells are defined by their sensitivity to the apoptosis-inducing effect of cross-linking agents, such as mitomycin C (MMC). The cloned FA disease genes, FAC and FAA, encode proteins with no homology to each other or to any known protein. We generated a highly specific antibody against FAA and found the protein in both the cytoplasm and nucleus of mammalian cells. By subcellular fractionation, FAA is also associated with intracellular membranes. To identify the subcellular compartment that is relevant for FAA activity, we appended nuclear export and nuclear localization signals to the carboxy terminus of FAA and enriched its localization in either the cytoplasm or the nucleus. Nuclear localization of FAA was both necessary and sufficient to correct MMC sensitivity in FA-A cells. In addition, we found no evidence for an interaction between FAA and FAC either in vivo or in vitro. Together with a previous finding that FAC is active in the cytoplasm but not in the nucleus, our results indicate that FAA and FAC function in separate subcellular compartments. Thus, FAA and FAC, if functionally linked, are more likely to be in a linear pathway rather than form a macromolecular complex to protect against cross-linker cytotoxicity.

scholarly journals Nuclear Import of Cdk/Cyclin Complexes: Identification of Distinct Mechanisms for Import of Cdk2/Cyclin E and Cdc2/Cyclin B1

1999 ◽  
Vol 144 (2) ◽  
pp. 213-224 ◽  
Author(s):  
Jonathan D. Moore ◽  
Jing Yang ◽  
Ray Truant ◽  
Sally Kornbluth
Keyword(s):  
Nuclear Localization ◽  
Nuclear Import ◽  
Mammalian Cells ◽  
Molecular Mechanisms ◽  
Cyclin E ◽  
Cyclin B1 ◽  
Transport Processes ◽  
Nuclear Localization Sequence ◽  
Nuclear Targeting ◽  
Importin Α

Reversible phosphorylation of nuclear proteins is required for both DNA replication and entry into mitosis. Consequently, most cyclin-dependent kinase (Cdk)/cyclin complexes are localized to the nucleus when active. Although our understanding of nuclear transport processes has been greatly enhanced by the recent identification of nuclear targeting sequences and soluble nuclear import factors with which they interact, the mechanisms used to target Cdk/cyclin complexes to the nucleus remain obscure; this is in part because these proteins lack obvious nuclear localization sequences. To elucidate the molecular mechanisms responsible for Cdk/cyclin transport, we examined nuclear import of fluorescent Cdk2/cyclin E and Cdc2/cyclin B1 complexes in digitonin-permeabilized mammalian cells and also examined potential physical interactions between these Cdks, cyclins, and soluble import factors. We found that the nuclear import machinery recognizes these Cdk/cyclin complexes through direct interactions with the cyclin component. Surprisingly, cyclins E and B1 are imported into nuclei via distinct mechanisms. Cyclin E behaves like a classical basic nuclear localization sequence–containing protein, binding to the α adaptor subunit of the importin-α/β heterodimer. In contrast, cyclin B1 is imported via a direct interaction with a site in the NH2 terminus of importin-β that is distinct from that used to bind importin-α.

scholarly journals A dominant-negative cyclin D1 mutant prevents nuclear import of cyclin-dependent kinase 4 (CDK4) and its phosphorylation by CDK-activating kinase.

1997 ◽  
Vol 17 (12) ◽  
pp. 7362-7374 ◽  
Author(s):  
J A Diehl ◽  
C J Sherr
Keyword(s):  
Cyclin D1 ◽  
Nuclear Localization ◽  
Mammalian Cells ◽  
Phosphorylation Site ◽  
Dominant Negative ◽  
Cyclin Dependent Kinase ◽  
Linker Peptide ◽  
Cdk Activating Kinase

Cyclins contain two characteristic cyclin folds, each consisting of five alpha-helical bundles, which are connected to one another by a short linker peptide. The first repeat makes direct contact with cyclin-dependent kinase (CDK) subunits in assembled holoenzyme complexes, whereas the second does not contribute directly to the CDK interface. Although threonine 156 in mouse cyclin D1 is predicted to lie at the carboxyl terminus of the linker peptide that separates the two cyclin folds and is buried within the cyclin subunit, mutation of this residue to alanine has profound effects on the behavior of the derived cyclin D1-CDK4 complexes. CDK4 in complexes with mutant cyclin D1 (T156A or T156E but not T156S) is not phosphorylated by recombinant CDK-activating kinase (CAK) in vitro, fails to undergo activating T-loop phosphorylation in vivo, and remains catalytically inactive and unable to phosphorylate the retinoblastoma protein. Moreover, when it is ectopically overexpressed in mammalian cells, cyclin D1 (T156A) assembles with CDK4 in the cytoplasm but is not imported into the cell nucleus. CAK phosphorylation is not required for nuclear transport of cyclin D1-CDK4 complexes, because complexes containing wild-type cyclin D1 and a CDK4 (T172A) mutant lacking the CAK phosphorylation site are efficiently imported. In contrast, enforced overexpression of the CDK inhibitor p21Cip1 together with mutant cyclin D1 (T156A)-CDK4 complexes enhanced their nuclear localization. These results suggest that cyclin D1 (T156A or T156E) forms abortive complexes with CDK4 that prevent recognition by CAK and by other cellular factors that are required for their nuclear localization. These properties enable ectopically overexpressed cyclin D1 (T156A), or a more stable T156A/T286A double mutant that is resistant to ubiquitination, to compete with endogenous cyclin D1 in mammalian cells, thereby mobilizing CDK4 into cytoplasmic, catalytically inactive complexes and dominantly inhibiting the ability of transfected NIH 3T3 fibroblasts to enter S phase.

scholarly journals Nuclear localization signals in phage terminal proteins provide a novel gene delivery tool in mammalian cells

2013 ◽  
Vol 6 (2) ◽  
pp. e22829 ◽  
Author(s):  
Modesto Redrejo-Rodríguez ◽  
Daniel Muñoz-Espín ◽  
Isabel Holguera ◽  
Mario Mencía ◽  
Margarita Salas
Keyword(s):  
Gene Delivery ◽  
Nuclear Localization ◽  
Mammalian Cells ◽  
Nuclear Localization Signals ◽  
Novel Gene ◽  
Terminal Proteins
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